The physiology and biology of blueberry fruit is the most important consideration for understanding postharvest storage. Fruit physiology is responsive to many stimuli including biotic, genetic, and environmental inputs. The extent to which a blueberry fruit are affected by these factors is largely cultivar dependent. The following studies address two aspects of blueberry fruit postharvest biology as it relates to pest control: In Chapter 2, we explore the effect of SO2 fumigation on five blueberry cultivars: 'Bluecrop', 'Draper', 'Elliott', 'Jersey', and 'Liberty' and the extent to which SO2 fumigation can be used to disinfest blueberry fruit of blueberry maggot (BBM) Rhagoletis mendax Curran. In Chapter 3, we use RNA sequencing (RNA-seq) to reveal genes differentially expressed (DE) in 'Elliott' fruit in response to infection by Colletotrichum fioriniae compared to mock- (water- ) inoculated fruit. By filtering out DE genes in mock-inoculated fruit postharvest, as well as DE genes in infected 'Jersey' and 'Draper' fruit, we discovered 113 genes unique to 'Elliott' fruit that are inoculation-responsive. This set of genes include canonical plant resistance genes as well as genes associated with secondary metabolite biosynthesis, cell wall metabolism, reactive oxygen species production and scavenging, and the hypersensitive response. These studies provide important groundwork for future blueberry breeding by identifying cultivars with genetics and physiology amenable to different interventions for reducing postharvest fruit losses.
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